There is a black Plunger Dump Valve on the top of the lift bag that releases the air from the lift bag. You can control the ascent of the lift bag by pulling the lanyard that is connected to this valve.

If you are using an Enclosed Floatation bag or Salvage Pontoon, you can find the Plunger Dump Valve on the side or corners of the lift bag.

No. The PDV is designed to be used on an open bottom lift bag so automatic release of air is not required. The system is designed to have the diver vent air by pushing the dump button located on top of the valve or by pulling the lanyard at the bottom of the bag.